Alright, so, after seeing some videos of the other lasnmasses of Tamriel (they're ALL in Skyrim), I grew envious of not being able to get there on the console due to noclip. But glitches still exist.

First off, you have to go to Morrowind'a border just north of Stendarr's Beacon. It's the only bordergate without an actual gate. Second, you need a horse (I used Shadowmere). Go through the arch of the gate until you can't physically go any further, then dismount after angling the horse to face away from the barrier. You should come through on the other side and... Bam! You're in Morrowind. It should be noted that you can't return, though if you wait for an hour or more, Shadowmere will spawn with you on the other side so that you can avoid walking.

It's incredible. Everything from Morrowind is there--Vvardenfell, the Red Mountain, Solstheim... All of it. I've only explored parts of Cyrodil, but the White-Gold Tower and the Imperial City's there... Makes me wonder if they'll add the other provinces for DLC. Anyways, enjoy.

Meant to post in the Cheats, Hints and Spoilers section. Accident happen. Mods, help?

Um not to ruin your fun. But you are aware that Morrowind would not be the same do to The Red Year.

What are you on about? It's a crappy, empty, not-entirely-correctly-made landmass with nothing on it. The Imperial city is not there. A basic white cylindrical shape representing white gold tower is there, that's it. The landmass is just designed to look like the rest of the world exists on your map or if you find somewhere to look out into that region. It doesn't actually have anything in it, and it's NOT the whole continent. Only half of Vvardenfell is there, for example, then it just dissapears. Solstheim is not there either.